{ "topology_description": { "type": "Single", "servers": [ { "address": "a:27017", "avg_rtt_ms": 5, "type": "Standalone", "tags": { "data_center": "dc" } } ] }, "operation": "read", "read_preference": { "mode": "SecondaryPreferred", "tag_sets": [ { "data_center": "nyc" } ] }, "suitable_servers": [ { "address": "a:27017", "avg_rtt_ms": 5, "type": "Standalone", "tags": { "data_center": "dc" } } ], "in_latency_window": [ { "address": "a:27017", "avg_rtt_ms": 5, "type": "Standalone", "tags": { "data_center": "dc" } } ] }